Step 1

What we’re going to create requires some work in Photoshop. Since this is mainly an After Effects tutorial, I will explain only the basics but it should be enough to get you through it. To start you need to take a picture of a building and open it in Photoshop.

Step 2

Next you should find 2 more pictures - one with building debris in it and other with broken windows.
Drag and drop debris image into building's composition.
Then, using rectangular marquee tool draw a rectangle around the place you want to use.

Step 3

Press the right mouse button and select Select Inverse, then hit Delete to erase all but what you need.
Change to the Move Tool and press Ctrl/Cmd+D to shut off the selection.
Now, using transform controls, align it against building's wall (hold Ctrl/Cmd for perspective adjustments)
I did it really quickly because I have a ready version prepared so the one below is far from perfect but you should spend some time getting it to align properly.

Step 4

Now take an Eraser Tool and erase unwanted stuff so the hole blends in better.
After you've done it, take a black brush, set its size to around 3 pixels and lower opacity to some 80%, draw edges around the hole. Then draw some fracture lines. Change brush size to 1px if necessary.

Create a new layer, then choose a brush type with 0% hardness (feathered edges), set its size to around 30px and lower opacity to around 20%. For better blending, set Blending mode to Linear Dodge(Add). Color around the hole (soot, burn markings etc.) and use Smudge Tool to correct it.

Step 5

Here's how you easily make a broken window.
Find a picture with a broken window in it (it can be monochrome also), then, using the same technique described above, align it with desired window and change its Blending Mode to Vivid Light. If necessary, you can color correct it. See both screenshot below.

Step 6

Go to After Effects and create a new composition. It can be whatever size you want. I went with 720p@25fps and half res. Duration too isn't important, just go with whatever you think is better.

Step 7

Start with importing your PSD as a composition. Then drag it to your main composition. Don't scale it down.
Since we're going to create flames in Particle Illusion, you need a background reference image for that.
Go to Composition>Save Frame As>File... In Render Queue set the settings to JPEG. Also go to Render Settings and set Resolution to Full.
Render it.

Step 8

Open Particle Illusion.
When it's open, double-click on that gray box left in your layer highlight and set just rendered JPEG as background.
When asked, press Yes to make the stage size same as image. Also notice the box right to the Loop icon in upper panel and change it from 120 to 500 frames so it'll give you 20 seconds of rendered material (on 25fps)

Step 9

The element you'll be creating in Particle Illusion is flames. You can also make smoke but I had some problems with it (alpha channel and lack of manual controls in AE) so I decided to make them using Particular.
What you need now, is to find the Flames preset in the right panel. At default it's in the Group 2 folder. Expand it and you'll find Flames at the bottom.
Now, click on it and move your cursor over your picture. Cursor will transform into a circle indicating that you can place emitter of particles.
Basically, you need to draw a line that will emit flames. It's important that you start from left, otherwise flames will go downwards. See the screenshot below and do something similar(click on lower left corner, then on lower right - afterwards, click right mouse button to stop the placing of points.)
Save your project.

Sidenote: I'm using full version of Particle Illusion 3 but since it's not that cheap, you can also use Particle Illusion SE which goes for around 95$. Main differences are the use of older engine (2nd), you can use only one layer of footage, it doesn't include blockers, forces, Super Emitters and it has a different interface. The Pro Emitters do not work with SE as well.

Step 10

Now, see the panel to your left. There you can find emitter properties.
First, right click on Flames 0 under Angle and choose Properties.
Then find Frames to Preload box and enter 200. This you'll have the emitter already emitted 200 frames before frame 1 in the timeline.

Step 11

If you press Play (preview), you'll see that flames are too fast. You need to change it by adjusting some properties.
Start with velocity by highlighting Velocity from emitter's pull-down menu.

Step 12

It's important that you're positioned at frame 1 in the timeline, otherwise you'll set keyframes which you don't need.
Bring down Velocity to 120% by pulling the red box.
Next, go to Weight and set it to around 15%
Then set Motion Randomness to 15%
You can preview and see that burning is slower but still, there are a lot of fast movement.
Save.

Step 13

Open Life properties and set it to 135%
The last thing you should change is the Zoom to around 80%
For this tutorial you're set but if you have a different scene you can try changing both Emission angle and Angle.
Disable Background by clicking on BG icon.

Save. Exit the software because you'll do the rendering with pIllusionRender. It should be in your Particle Illusion directory.

Step 14

Open pIllusionRender.exe and press OK if prompted.
Set your Project File and Output. I suggest to output as TIFF sequence (you need a format with Alpha channel).
Press Save.

Step 16

In AE, import it as image sequence with Straight-Unmatted Alpha. Then right mouse button on it and hit Interpret Footage>Main. Set Frame Rate to 25.
Next, drag and drop it into timeline and you'll see that the colors are completely wrong and doesn't match to our scene.
Apply Tint and Curves and configure them as you see in screenshot.
Save.

Step 17

It's time to set track-matte. Create new, white solid, which will serve for this purpose.
Using Pen-tool, apply a mask around lower and right edge of the hole from which the fire will come.
Also apply new mask to the wall in the middle so that fire wouldn't cross it.
See the screenshot and set the Feather options accordingly.

Now, highlight flames layer and set her's Track-matte to Luma Inverted. Don't forget to enable Eye Icon of flames if you have disabled it as i did.
Save.

Step 18

As I mentioned earlier, we're going to use Particular for smoke so create a new solid. Apply Particular to it.
Next, set Particles/sec to 80 which will, basically, be the density for smoke so if you want them to be less dense lower it later.
Because the hole is rectangular shaped, set Emitter Type to Box.

Obviously, Direction should be set to Directional as smoke raise in only one direction.
Now we need to set up an angle which, I guess, is self explanatory:
X Rotation: 115
Y Rotation: -30

Z Rotation: 40

We want them to move slowly because, as you know, things look slower when they are afar. Velocity must be lowered:
Velocity: 40
Velocity Random: 0
Velocity from Motion: 0

You can also set Emitter Size Z to 0 because flat smoke looks good enough. It can save you a little render time.
Save.

Step 19

Go to Particle pull-down and change these settings:
Life to 15 which is a longevity of our smoke.
Particle Type: Cloudlet - Sphere should also work but i prefer Cloudlet because of it's irregular shape.
Cloudlet Feather: 100
Size: 25
Opacity: 10
Opacity Random: 50
Color to Dark Gray
Now it starts to look something like smoke.

Under Physics:
Wind X: -5 to simulate a little wind.

Save.

Step 20

Now, apply Turbulent Displace (Effect>Distort>Turbulent Displace)
Set settings as shown in screenshot.
The key setting is Complexity which gives that cloudy look. Amount should be low because we want to leave the form as it is and not displaced all around.
To get more organic and irregular look, raise the Y values for Offset (Turbulence)

Change of Evolution isn't mandatory so you can change it as desired.

Step 21

It's time to change the Position XY for Smoke Emitter. Do that as shown or whatever you want.
Also offset Smoke layer in timeline so at Frame 0 particles would be fully emitted.
Save

Step 22

Create a new, white solid for Smoke Track-matte. Again, draw a mask as shown in screenshot. Set Feather to 90.
Highlight Smoke layer and set it's Track-matte to Luma Matte.
Then Highlight both Smoke and Smoke_matte layers and move them under flame layers.
Save.

Step 23

You can clearly see that flames are too big. Highlight their layer and change its position downwards.
Thanks to Track-matte, you can do it freely.

Save.

Step 24

As you saw in preview, there are stuff falling down from sky. Create a new solid and apply Particular to it.
Set these settings:
-Emitter pulldown-
Particles/sec: 50 - it'll be the amount of those flying things, later you can adjust as necessary
Emitter Type: Box - obviously, as you need them to fill the whole screen evenly
Position Z: 20 - you can change it for depth
All 3 Velocity settings: 0 - since we don't want them to do flying on their own (physics does the work)

Physics pulldown
Gravity: 5
Spin Amplitude: 90 - this is really important, it will give turbulence and random, organic movement as they fall
Wind X: -40 - does what it says

After this, change emitter's Position XY so that you can't see emitting particles (set Y value to around -1000). Offset the layer accordingly in timeline.
Save.

Step 25

The only element left is those small firey things falling from the burning opening.
Again, create a new solid and apply Particular.
Really few particles are necessary so set Particles/sec to 10
Emitter Type: Box
Direction: Directional
X Rotation: 90
All 3 Velocities: 0 - we're going to use the almighty gravity again
Emitter Size X: 100
Emitter Size Z: 200
You can set Emitter Size Y to 0 because that will be masked anyway

Set Opacity over life and change emitter's position as shown in screenshot. Don't forget to offset the layer in timeline.
Save.

Step 26

Create new, white solid which again will be used as a track matte layer. Draw a mask as in screenshot and then set the Firely_stuff layer's track matte to Luma Inverted. Also set it's Blending mode to Add. Save. All the elements are set and you can carry on with color correction.

Step 27

For easier color correction Pre compose everything into a single composition. Call it a Final_Comp or whatever you want.
You can try correcting on your own but here is what I used:
Hue/Saturation - Blue channel Saturation at -50 and Lightness at -26
An S Curve for contrast and some Levels adjustments to make the scene darker.
Plus I used Noise effect with Amount of Noise set to 7% and Use Color Noise unticked for more realistic look.
You can try to change the Blending mode for flames to Add also.

Step 28

In addition you can add a glow around the fire. Create a new, orange solid. Draw a mask around the fire, set hers feather to 120 and opacity to 70%. Then change the Blending mode to Overlay. At last, set the expression for Opacity as follows: wiggle(1,20)
See the screenshot.
Save.

Step 29

You're done. Furthermore you can add a camera and animate it for movement. If you're doing that, go back to Main_Comp, open it's Composition Settings and expand it's dimensions for more flexibility. If necessary expand particle layers too.